1. Field of the Invention:
This invention relates to a slider for slide fasteners, and more particularly to such a slider which is automatically lockable on the slide fastener.
2. Prior Art:
Automatic lock sliders are known, a typical example of which comprises a slider body including upper and lower wings, a pull tab, a locking member, a resilient member and a casing, the locking member being interposed between the pull tab and the resilient member and normally urged in a direction to lock the slider in position on the slide fastener. One such known slide fastener slider disclosed in Japanese Utility Model Publication No. 55-17846 has a resilient member in the form of a leaf spring accommodated in a casing, the spring being supported on a piece of the material of the casing which has been cut and bent adjacent to an opening in the casing through which a pull tab is pivotably mounted. This slider construction has a drawback in that it is not only unsightly in appearance but also mechanically frail because of the presence of such cut and bent piece in the portion of the casing which is subjected to pulling forces upon manipulation of the pull tab.
Another prior art example is shown in U.S. Pat. No. 4,102,022 issued July 25, 1978 in which a slider has a leaf spring supported at opposite ends in recesses formed in a casing. Since it is difficult to hook both ends of the spring in such recesses, the spring being often aloof in the upper portion of the casing, there is provided a tongue-like projection on the leaf spring for engagement with a locking prong to ensure locking of the slider. This structure however necessarily requires increased height of the casing to accommodate such a leaf spring, and hence requires so much thickness of the slider as a whole which makes the slider look unsightly and cumbersome to manipulate.